This invention relates to handling tubing used in medical procedures. For example, the invention may be used in connection with delivering and installing tubular grafts into a patient's body to repair, replace, or supplement a patient's natural body organ structures or tissues. The invention is especially useful in connection with inserting such grafts into a patient through the patient's existing arteries and veins.
Several procedures are known for revascularizing the human heart in order to treat a patient with one or more occluded coronary arteries. The earliest of these procedures to be developed involves exposing the heart by means of a midline sternotomy. Following surgical exposure of the heart, the patient's aorta and vena cava are connected to a heart/lung machine to sustain vital functions during the procedure. The beating of the heart is stopped to facilitate performance of the procedure. Typically, a suitable blood vessel such as a length of the patient's saphenous (leg) vein is harvested for use as a graft. The graft is used to create a new, uninterrupted channel between a blood source, such as the aorta, and the occluded coronary artery or arteries downstream from the arterial occlusion or occlusions.
A variation of the above procedure involves relocating a mammary artery of the patient to a coronary artery.
Although the above-described sternotomy procedures are increasingly successful, the high degree of invasiveness of these procedures and the requirement of these procedures for general anesthesia are significant disadvantages. Indeed, these disadvantages preclude use of sternotomy procedures on many patients.
More recently, less invasive procedures have been developed for revascularizing the heart. An example of these procedures is known as thoracostomy, which involves surgical creation of ports in the patient's chest to obtain access to the thoracic cavity. Specially designed instruments are inserted through the ports to allow the surgeon to revascularize the heart without the trauma of a midline sternotomy. Drugs may be administered to the patient to slow the heart during the procedure. Some thoracostomy procedures involve relocating a mammary artery to a coronary artery to provide a bypass around an occlusion in the coronary artery.
Thoracostomy bypass procedures are less traumatic than sternotomy bypass procedures, but they are still too traumatic for some patients. Also, the number of required bypasses may exceed the number of mammary arteries, thereby rendering thoracostomy procedures inadequate to fully treat many patients.
Another technique for revascularizing the human heart involves gaining access to the thoracic cavity by making incisions between the patient's ribs. his procedure is known as thoracotomy. It is also substantially less traumatic than midline sternotomy, but it is still too traumatic for some patients.
In view of the foregoing, even less traumatic approaches have been developed for revascularizing a patient, as described in Goldsteen et al. U.S. patent application Ser. No. 08/745,618, filed Nov. 7, 1996, and hereby incorporated by reference herein in its entirety. With such approaches, grafts (e.g., of saphenous veins) can be delivered to an operative site in the patient through the patient's existing arteries and veins. Grafts are typically inserted between two attachment sites in the patient's existing body organs (e.g., between a site along the patient's aorta and a site along the coronary artery downstream from a coronary artery occlusion).
A number of instruments are used to perform the different tasks associated with such a grafting procedure. One important instrument is the tubular graft insertion instrument used for graft delivery and attachment. Prior to insertion of the graft in the body, the graft is placed over the end of this instrument. Two small inflatable balloons, which are located a fixed distance from one another along the length of the instrument, are partially inflated to hold the graft in place. The graft is then inserted into the patient and aligned with the attachment site. When each end of the graft is aligned, the corresponding balloon is further inflated to drive prongs of a corresponding pronged attachment ring through the graft into the patient's tissue at the attachment site.
This type of graft insertion instrument can be used in a variety of situations. However, the fixed pacing between the two small balloons restricts the lengths of grafts that may be inserted with any given instrument. It is therefore an object of the present invention to provide methods and apparatus for inserting variable length grafts into a patient.